1. Technical Field
The present invention relates to a liquid jet head which jets liquid droplets onto a recording medium to perform recording and a liquid jet apparatus.
2. Related Art
In recent years, there has been used a liquid jet head of an ink jet system which ejects ink droplets onto, for example, recording paper to record characters or figures thereon, or ejects a liquid material onto the surface of an element substrate to form a functional thin film thereon. In this ink jet system, liquid such as ink and a liquid material is guided from a liquid tank into a channel through a supply tube, and pressure is applied to the liquid filled in the channel to thereby eject the liquid as liquid droplets from a nozzle which communicates with the channel. In the ejection of liquid droplets, characters or figures are recorded, or a functional thin film having a predetermined shape or a three-dimensional structure is formed by moving the liquid jet head or a recording medium.
A liquid jet head of an ink jet system includes a pressure chamber to which liquid such as ink is introduced, a driver element which drives the pressure chamber, a drive circuit portion which generates a drive waveform and supplies the drive waveform to the driver element, a nozzle which communicates with the pressure chamber and ejects liquid inside the pressure chamber therefrom, and the like. In the driver element, there is used a system that generates pressure waves in liquid filled in the pressure chamber using a piezoelectric effect of a piezoelectric body and ejects liquid droplets by the pressure waves or a system that heats a heat generator provided in the pressure chamber to generate air bubbles in liquid filled in the pressure chamber and ejects liquid droplets by pressure waves generated along with the generation of the air bubbles. When driving the pressure chamber, the driver element itself generates heat and the drive circuit portion which generates a drive waveform also generates heat.
JP 2006-212795 A describes a configuration that performs cooling of a head portion in which a driver element using a piezoelectric body is formed and cooling of a drive circuit portion which generates a drive waveform. FIG. 8 is a perspective view of an ink jet printer head 105 described in JP 2006-212795 A. FIGS. 9A and 9B are explanatory diagrams of a temperature control base 151 for the ink jet printer head 105 described in JP 2006-212795 A. The ink jet printer head 105 is fixed onto the temperature control base 151 to cool a part of the inkjet printer head 105 required to be cooled. The ink jet printer head 105 mainly includes an ink ejecting portion 121 and a drive waveform generating portion 122. The ink ejecting portion 121 includes a PZT substrate 124 which is covered with a top plate 125 and a nozzle plate 126 which is fixed to the tip part of the ink ejecting portion 121. The PZT substrate 124 has a plurality of grooves (not illustrated) which are covered with the top plate 125 to constitute pressure chambers. Ink is supplied to the pressure chambers through an ink supply tube 127. The drive waveform generating portion 122 includes a circuit board 128 which is coupled to the ink ejecting portion 121. The circuit board 128 includes a first board 128a which is directly fixed to the ink ejecting portion 121 and a second board 128b which is coupled to the first board 128a and provided with a connector 130. A driver IC is disposed on the lower face of the first board 128a. When the driver IC generates a drive waveform and the generated drive waveform is applied to drive electrodes (not illustrated) which are formed on supports located on opposite sides of each of the pressure chambers, the supports are deformed by a piezoelectric effect and the volume of each of the grooves thereby changes. As a result, the ink filled in the pressure chambers is ejected from nozzles 123. As this point, the driver IC and the PZT substrate 124 generate heat.
The temperature control base 151 includes a first base 152 and a second base 153 which are coupled to each other through an adhesive layer 154. The temperature control base 151 is fixed to the lower part of the ink jet printer head 105. A structure base 151a is attached to the lower part of the temperature control base 151. The first base 152 is fixed to the ink ejecting portion 121 and cools the PZT substrate 124 of the ink ejecting portion 121. The second base 153 is fixed to the drive waveform generating portion 122 and heats the driver IC. The first base 152 is provided with a liquid circulation tube inside thereof. The liquid circulation tube of the first base 152 is coupled to two first coupling portions 155. The second base 153 is provided with a liquid circulation tube inside thereof. The liquid circulation tube of the second base 153 is coupled to two second coupling portions 156. Cooling liquid is circulated through the first coupling portions 155 and the second coupling portions 156 to thereby release heat to the outside. Water or oil is used as the cooling liquid.
JP 2005-279952 A describes a configuration that prevents deterioration of recording quality caused by a difference in temperature of ejection ink depending on nozzle installation locations. When a difference in temperature of ejection ink is generated depending on nozzle installation locations, the ejection characteristics change according to the difference in temperature of ink. Accordingly, the recording quality on a recording medium is deteriorated. Thus, an IC chip which generates a drive waveform for driving a head portion is coupled to a heat release member, and the heat release member is routed up to the vicinity of an ink supply member of the head portion. As a result, heat generated by the IC chip is transmitted through the heat release member and then released near the ink supply member. Ink in the ink supply member is heated by the released heat, thereby reducing temperature variations between various locations of ink.
The ink jet printer head 105 described in JP 2006-212795 A is capable of independently cooling the PZT substrate 124 and the circuit board 128. However, it is necessary to connect the ink supply tube 127 for supplying ink to the head portion, two outgoing and return cooling tubes for cooling the PZT substrate 124, and two outgoing and return cooling tubes for cooling the circuit board 128 to the ink jet printer head 105. Thus, it is necessary to connect five liquid circulation tubes in total between the head portion and the control portion. Therefore, many components are required, and assembly thereof becomes complicated. JP 2005-279952 A describes the configuration which uses heat generated by the IC chip for driving the head portion. However, JP 2005-279952 A fails to describe a configuration and a method for efficiently cooling the IC drive chip.